mcarterbrown.com  

Tiberius Arms Everything Tiberius

Reply
 
Thread Tools Search this Thread
Old 02-21-2010, 12:59 AM   #21 (permalink)
Active Member
 
CovertRssian's Avatar
 
Join Date: Jan 2010

Quote:
Originally Posted by sparky View Post
So it shot like ever other 12 gram based marker? I see no reason for concern...
Correction it shoots like any other marker on CO2

Quote:
Originally Posted by brycelarson View Post
I've got a TPX. they use a similar system to the Tib guns. it's a dump valve out the back of the reg - you set velocity then lower the dump valve until it just leaks - then tighten it back a touch. With the CO2 up front I would have to shoot up in the air then over the chrono.

and yes, the SA8 will vent at some point I assume - just at pressures that will get the velocity way over 300 fps. I'm curious what the highest pressure the T8's dump valve will allow - or more specifically, how fast it will let the gun shoot.
I hit 380 FPS with the regulator not even all the way turned in. I didn't want to try any higher with the paintballs. I believe someone said they hit 450 FPS, because their chrono wouldn't read above that.

Quote:
Originally Posted by Mayvik View Post
Sounds like between some combination of adjusting the velocity down, filling the extra volume, and lightening the relief valve spring, it should be pretty easy to make these "safe".


Quote:
Originally Posted by Dirty Deuce View Post
I think the spikes have more to do with the reg springing, and volume chamber. Someone else also mentioned theirs became more efficient after a break in period.
I can imagine a break in period helping, only problem is regs take about 2k shots to break in? Without an external air source, that could get very expensive.
CovertRssian is offline   Reply With Quote
Old 02-21-2010, 01:26 AM   #22 (permalink)
Active Member
 
Join Date: Apr 2008
Location: Danville, VA

I would love to see an identical test done with a properly adjusted T-8. Any idea if and when that can be done?
__________________

Μολὼν λαβέ - Molōn labe - ΜΟΛΩΝ ΛΑΒΕ - Come and take them!
DoW - Outlaw - "we're brothers. I protect them, they protect me.”
Magic is offline   Reply With Quote
Old 02-21-2010, 08:29 AM   #23 (permalink)
la la la la revolution
 
Join Date: Oct 2006
Location: MN

Quote:
Originally Posted by Dirty Deuce View Post
I think the spikes have more to do with the reg springing, and volume chamber. Someone else also mentioned theirs became more efficient after a break in period.
The first two mags show a pretty reasonable consistency level (especially considering the horrible paint). But when I deliberately tried to get liquid CO2 past the regulator, the velocity spiked upwards a lot. I believe that's the reason for the spike, and why I think an adjustable relief is necessary.


Today I'm going to turn up the reg (slowly) until the pressure relief starts to activate, then record the velocity of a couple of shots. Good thing I have some 1/4" thick sheets of FR4 to act as a backstop...
MondoMor is offline   Reply With Quote
Old 02-21-2010, 08:59 AM   #24 (permalink)
Banned
 
alpha434's Avatar
 
Join Date: May 2008

AKA Fan
You guys can try putting the springs in a vise overnight to break them in... Old trick for automags.
alpha434 is offline   Reply With Quote
Old 02-21-2010, 11:39 AM   #25 (permalink)
la la la la revolution
 
Join Date: Oct 2006
Location: MN

This post by Mayvik is interesting:
Quote:
Originally Posted by Mayvik View Post
... When I first slam the mag home, there's a little poof (very slight, less than ejecting a mag) out of the modified relief valve....
In my test, mag 3's first shot was very hot. Maybe a modded valve like Mayvik's would've kept that from happening.

Do T8/T9 owners see this when they insert mags?
MondoMor is offline   Reply With Quote
Old 02-21-2010, 11:58 AM   #26 (permalink)
Active Member
 
CovertRssian's Avatar
 
Join Date: Jan 2010

Quote:
Originally Posted by alpha434 View Post
You guys can try putting the springs in a vise overnight to break them in... Old trick for automags.
Do continue? Which spring would it be?
CovertRssian is offline   Reply With Quote
Old 02-21-2010, 12:47 PM   #27 (permalink)
Newbie
 
Join Date: Feb 2010

Quote:
Originally Posted by cool0 View Post
good job! the only thing I don't understand is.... why did you turn the gun upside down? what did that prove? or did I read that wrong? also I agree with Mann. turn the velocity down to 250fps(or lower) that way when a spike comes along you are good to go. also Wingman, do you think that dryfiring would help break the gun in?
Didn't dry fire I shot reballs through it.....reballs are 68 cal. rubber balls....
WingMan56 is offline   Reply With Quote
Old 02-21-2010, 02:14 PM   #28 (permalink)
Inch of Gold
 
Mayvik's Avatar
 
Join Date: May 2007
Location: Denver

Fan of EMR
CCM Fan
AKA Fan
Brass N Wood Fan
Palmers Fan
PBN Fan
OK all, I finally got around to doing some quick and dirty testing for my quick and dirty mod. Unfortunately it seems like I got even less meaningful data than MondoMor, but I'll give you the PowerPoint summary.

Test apparatus was an SA-8 with the MayvikMod5003 relief valve, 2 mags, 2 old-*** Crosman cylinders from probably the early-mid 90s, and the 3 cylinders that came with the gun. I was using reballs (unsure if generic or ReBalls(TM)).

Test location was Mayvik's Master Bathroom, approximately 72-75 degrees F, no air impingement, and firing into my shower curtain as a backstop from about 3 feet. In case of ricochet, mask was worn but cup was not, thankfully no tester's testes were harmed in the making of this data.

I turned the reg screw in some random amount to start with. It wasn't bottomed out on either end, and there was plenty of adjustment length left in either direction. Turns out that gave me pretty much field useable velocity so I just left it there. It was not adjusted at all during the test.

I was not able to replicate MondoMor's inverted tests, because whenever I inverted the gun it invariable caused some sort of technical issue that resulted in me having to tear it down and reset the bolt.

Technical difficulties abounded during this test and by the end I was ready to punch my gun in the groin if it had one. Reballs fed like crap, and I had them stuck in the mag a couple of times causing me to shoot blanks. I was actually getting the reballs stuck in the barrel fairly often, maybe 1/6 near the end of the test (I have no idea how this is possible, I guess my balls are swollen or larger than normal?), which resulted in all kinds of weird problems such as the relief valve venting, the bolt not recocking, and dumping gas out of the chamber port or down the barrel. When this happened sometimes I could just pull the barrel and pop the ball out, other times I had to reset the bolt. I got very few shots per mag (maybe 16?) due to all the issues with venting down the barrel, and frequently ejecting mags to reset the bolt or clear the bore.

My first string (the only complete mag I fired that I didn't have some technical difficulties with) was:

235 276 278 267 263 249 248 308

The just as I was pulling the trigger on the 308, the modified relief vent started to hiss a bit. Several later shots fired in the 29x range without the relief valve triggering. The hottest shot I was able to get was 332, with a couple in the 320s. All of those shots were fired -while- the relief valve was venting. The relief valve vents slooooowly; 2-3 seconds for it to stop.

Mayvik's Conclusions: I'm just going to go ahead and post my conclusions now about what this means and if I'm wrong so be it, crow tastes like chicken anyway.

1) SA-8s suck. I love my T8, but this thing is a mess and shoots all over the planet consistency-wise. I'm going to chalk it up to the big volume. I also cannot believe how many times I had to take this thing apart and reset the bolt, fidget with the sears, etc. Not acceptable. Assuming Tib manages to sweeten the deal (cash instead of cert, or slightly less $ and keep your mags), I'll probably be turning mine in.

2) My modified relief valve concept works. Sorta. It still allows you to shoot reasonable field velocity (up to 300), but will also still vent in an overpressure situation. If 330ish is the top fps that you can shoot with this mod installed, that's not brutally, instant-death unsafe and I feel significantly more comfortable playing with that setting, especially if the gun is chrono'ed down in the 260-270 range instead of 280-300. Based on the fact that I was getting a "slow" release of pressure, I think it's just not venting fast enough and the 1/16" hole I drilled to vent should probably get upsized to just slightly smaller than the ID of the relief spring. This is just logical and is consistent with the large allen key hole on the T8's relief valve.

3) If you are getting a relief valve burst..don't shoot while it's happening, because you can still get a hot shot until the pressure has equalized. Hopefully a larger vent hole will fix this so a relief burst takes <1s and you can get back to pwning foos in a more timely fashion.

I'm not going to dork around with this anymore until we have some dialog with Tiberius about what the options are. A few reasons for this..1) I am out of 12 grams 2) trying to test stuff in the bathroom of your apartment using reballs is not very meaningful and 3) I'm a lazy bitch. Thanks to everyone else who is continuing to work on these and keeping the tinker/tester spirit alive.
__________________
My Feedback
Mayvik is offline   Reply With Quote
Old 02-21-2010, 03:38 PM   #29 (permalink)
drg
Banned
 
Join Date: Mar 2007

Can you post the numbers from the T8 that back up your conclusion?
drg is offline   Reply With Quote
Old 02-21-2010, 03:46 PM   #30 (permalink)
Active Member
 
Join Date: Aug 2009

wow, sounds like you've found a solution!

Dora the Explorer voice:
"you did it! hooray!"
ajmidget is offline   Reply With Quote
Reply

  mcarterbrown.com » Paintball » The Armory » Tiberius Arms

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump


All times are GMT -4. The time now is 01:02 PM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO
© MCB Network LLC